The present invention relates to a selective release assembly for gripper clamps. Gripper clamps are commonly used in conveyor assemblies of sheet material handling apparatus to convey sheet material articles, such as newspapers or magazines, from one location to another. U.S. Pat. No. 4,638,906 shows a conveyor assembly which includes a plurality of gripper clamps connected by a conveyor chain and movable along a track. Some examples of known gripper clamps are shown in U.S. Pat. Nos. 4,681,213; 4,320,894; and 4,921,294.
Some gripper clamps are spring biased into a closed or clamping position for holding sheet material such as a book. It is desirable to be able to open selected gripper clamps moving past a particular point on a conveyor assembly, in order to release the sheet material articles held in the selected gripper clamps.